1. Field of the Invention
This invention pertains generally to treating bone fractures, and more particularly to an external fixation apparatus for treatment of fractures and malunions of the distal radius which eliminates the need for bone grafting.
2. Description of the Background Art
External fixation devices are well known in the field of orthopedic medicine, and such devices are widely used to support and align a fractured bone to facilitate healing. External fixators commonly include a frame made from interconnected bars and full or partial rings having a number of holes, where the rings fit partially around the bone, or completely surround the bone. Additionally, single rings can be used or multiple spaced-apart rings can be used. The devices are then secured to the bone using transfixating wires or pins and/or non-transfixating pins. Transfixating wires and pins pass laterally through the bone and are typically connected at opposite ends to the frame, whereas non-transfixating pins are introduced into the bone without completely transversing it. Once the pins or wires are inserted in the bones and tissue, small adjustment to the alignment to the frame with respect to the bone are typically made by removing, realigning and reattaching components to the bone.
A common problem with the majority of external fixation systems used for the distal radius is that they are only capable of maintaining a reduction that is obtained manually. Such systems apply ligamentaxis in a longitudinal fashion without concern for the three dimensionality of the fracture deformity. One device that is available, known as the Agree Wrist Jack, has attempted to solve this problem by applying ligamentaxis in several planes, and the technique is referred to as "multiplanar ligamentaxis" in the medical field. This device, however, tries to achieve reduction in a stepwise fashion; that is, a deformity is corrected sequentially in one plane at time. Unfortunately, however, correcting one plane of deformity creates a block to correcting the second plane of deformity due to the ligamentous anatomy. While the Agee Wrist Jack is the current state of the art in distal radius fracture fixation, it suffers from the lack of appreciation that a fracture deformity is three dimensional and exists in only one plane.
In an attempt to solve this problem, devices have been developed to direct the force against the single isolated plane of deformity. For example, the Ilizarov methodology of fracture fixation employs a huge assortment of rings and pieces of equipment that look very similar to an erector set, and use of the equipment requires special training. The frame is fashioned from the rings and rods using nuts and bolts, with complicated assembly being required each time that a frame is set up for a particular patient. In addition, the device requires complicated disassembly and, in effect, rebuilding of the frame configuration to make periodic adjustment. Most surgeons who treat fractures are intimidated by the complexity of such equipment.
In addition, the current state of the art for correcting distal radius malunions is surgical osteotomy of the bone followed by bone grafting with plate fixation. This requires harvesting the bone from the iliac crest, thus creating more morbidity. It also leaves a plate and screws in a person which can cause future problems. While the Ilizarov methodology can be used to avoid a bone graft, the equipment is very complex as described above.
Therefore, there is a need for an external fixation device that can be used for both fracture treatment and malunion treatment of the distal radius in the forearm, that does not require complicated assembly and disassembly, and that will direct the applied force against the single isolated plane of deformity. The present invention satisfies those needs, as well as others, and overcomes the deficiencies in currently available technology.